Elucidating the N−N and C−N Bond‐breaking Mechanism in the Photoinduced Formation of Nitrile Imine

Abstract

AbstractIn this study, we revealed the significance of chemical bonding for the photochemically induced mechanism of 2‐phenyl tetrazole derivatives generating nitrile imines. The correlated electron localization function shows that the formation of imine nitrile involves two key bond events: (i) the heterolytic C−N breakage taking place in the T1 state and (ii) the homolytic N−N rupture occurring in the T2 excited state. In particular, a cation‐radical specie results from the C−N cleavage, whereas the N−N rupture creates a biradical resonant form of imine nitrile. Additionally, we noticed that the substantial pair delocalization of the C−C‐N bonded structure could play a significant role in the conversion of the biradical imine nitrile into both the propargylic and allenic forms via the T1→S0 deactivation.